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UNITED STATES DEPARTMENT OF AGRICULTURE. 

Department Circular 115. 



Bureau of Plant Industry 
(New and Rare Seed Distribution), 

WM. A. TAYLOR, Chief. 



ALFALFA. 



Instructions adapted to southern New Jersey, Delaware, southern Maryland, Virginia, Arkansas, 
Tennessee, and the South Atlantic and Gulf States. 

(These instructions are intended primarily for those soils that are not of lime- 
stone origin.) 

Object of the distribution. — The distribution of new and rare seeds has for 
its object the dissemination of new and rare crops, improved strains of staple 
crops, and high-grade seed of crops new to sections where the data of the depart- 
ment indicate such crops to be of considerable promise. Each package contains 
a sufficient quantity for a preliminary trial, and where it is at all practicable 
the recipient is urged to use the seed for the production of stocks for future 
plantings. It is believed that if this practice is followed consistently it will 
result in a material improvement in the crops of the country. Please make a 
full report on the inclosed blank regarding the results you obtain with the seed. 

DESCRIPTION. 

Alfalfa {Medicago sativa) is a deep-rooted, hardy, perennial forage 
plant, belonging to the family which includes beans, peas, and clover. 
It occupies the same place in western agriculture that cowpeas and 
clover fill in the eastern third of the United States. As a hay crop, 
alfalfa is to be preferred to red clover in the eastern portion of the 
country whenever it can be successfully produced. It is equal, if not 
superior, to the latter in feeding value and yields a greater tonnage 
per season. Good cowpea hay is almost equal to alfalfa in feeding 
value, but the number of crops alfalfa produces in one season makes 
the total yield per acre much greater than that of cowpeas. Alfalfa 
is also more easily cured. Since it is perennial, it will last a number 
of years unless crowded out by weeds or otherwise destroyed. 

SOIL REQUIREMENTS. 

A deep, fertile, well-drained, nonacid soil, reasonably free from 
weeds, is required. While the crop has been made to grow on soijs 

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2 Department Circular 115, U. S. Dept. of Agriculture. 

of almost eveiy texture, still its production on deep sands has not 
generally been a profitable undertaking. It is practically useless to 
sow alfalfa on thin soils where the bedrock approaches the surface, 
on land underlain by hardpan, or in locations where the subsoil is so 
compact that the roots can not penetrate it to considerable depths. 
It is also equally useless to attempt to grow alfalfa on land where the 
water table comes near the surface. In porous soils that conduct 
water readily, standing water at 4 or 5 feet may be injurious. In the 
closer textured soils, however, the water table may with safety be at 
somewhat shallower depths, but even then it would be inadvisable to 
attempt the cultivation of this crop with standing water nearer than 

3 feet below the surface. For the purpose of ascertaining the char- 
acter of the soil and subsoil and also the depth of the water table, 
frequent borings should be made with a soil auger. In determining 
the adaptability of a tract of land to alfalfa, this auger will generally 
be of greater assistance than a chemical analysis of the soil. 

Not only should the land have good underdrainage, but the surface 
should have sufficient slope to carry off the surplus water readily. 
Rich river or creek bottom lands which are subject to overflow are 
well suited to the crop, provided these overflows are not of long 
duration and the land is well drained. 

PRECEDING CROP. 

When once started under favorable soil conditions, weeds will 
likely prove the most dangerous enemy. For this reason it is best 
to precede alfalfa for one or two years with crops which are either 
clean cultivated or which themselves choke out the weeds, as, for 
instance, cowpeas. As a general thing, seedings on sod lands have 
not been successful and are not recommended. Early truck and 
potato crops furnish excellent opportunities for destroying weeds 
and may generally be taken off the land in time to give ample oppor- 
tunity to prepare it for fall seeding. The crop can also follow oats 
and wheat to good advantage, provided the land has previously been 
treated in such manner as to destroy most of the weeds. Excellent 
results are also secured on summer fallow, but this system is often 
objected to on the ground that it results in the loss of the use of the 
land for a large part of the season. 

PREPARATION OF LAND. 

Many of the failures to secure a good stand of alfalfa may be traced 
directly to the improper condition of the seed bed. The soil should 
be fine and loose for the upper 2 or 3, inches, and below that it should 
be sufficiently firm to favor,, capillary action, yet porous enough to 
insure good drainage and aeration. If possible, at least six weeks 

N0V1 



*A^W4 c f Alfalfa. 3 

^ should intervene between the time of plowing and that of seeding. 
Frequent harrowing should be given to settle the ground, produce 
^S the necessary fine tilth, and destroy the weed seedlings as they 
X start. Moreover, the land should contain a fair supply of humus. 
This can be supplied by applications of well-rotted, weed-free 
stable manure. Where this is not available, it is desirable to plow 
under some green-manure crop, such as red, crimson, or bur clover, 
cowpeas, soy beans, or rye and vetch, the kind of crop depending 
on the locality. Cowpeas can not well be plowed under in time for 
planting alfalfa in the same season, as the vines do not have an 
opportunity to decay before time for planting. They can be plowed 
under the autumn previous and the land sown to crimson clover or 
rye and vetch that fall or to cowpeas the following spring. If sown 
again to cowpeas, they should be sown early, mowed, and the stubble 
disked and repeatedly harrowed to bring the land into the necessary 
well settled and finely pulverized condition for alfalfa. Red or 
crimson clover or rye and vetch can be plowed under and the ground 
harrowed frequently until late summer or early fall, when the seed- 
ing should take place. Where alfalfa is to follow wheat or oats 
the land should be double disked just as soon as these crops are 
removed and harrowed every week or 10 days until time for seeding. 
If it is to follow potatoes or some other truck crop and the field is 
clean, rich, and mellow, the potato vines or other refuse should 
be raked off, the land disked, and then put into fine tilth with a 
spike-tooth harrow. In sections where considerable silage corn is 
produced, successful stands of alfalfa are sometimes obtained by 
seeding after the corn is removed, the land being treated in prac- 
tically the same manner as where the crop follows early potatoes. 

LIMING. 

Practically all the soils in the region under consideration are 
benefited by applications of lime. It may be applied with a manure 
spreader, a fertilizer distributor, a lime distributor, or by hand. 
Any method which spreads the lime uniformly and at low cost is 
satisfactory. It should be applied at least two or three weeks before 
seeding, in order that it may become thoroughly incorporated with 
the soil. At least a ton of burned lime is generally required, and 
larger applications are often necessary on the heavier soils. If 
ground limestone or ground oyster shell is to be used, the quantity 
should be double that of the burned lime. Experiments have shown 
very little difference in the final results obtained from the different 
forms of lime. Burned lime will give quicker results, but the ground 
limestone and ground oyster shell will finally give the same benefit. 
The essential element in lime of any form is the calcium oxid, and 



4 Department Circular 115, U. S. Dept. of Agriculture. 

it is recommended that the farmer use whichever form of lime is 
cheapest, based upon the percentage of this element present. Where 
the consumer paj^s the freight, it should be remembered that he will 
not only have to pay such charges on practically twice as much of the 
ground limestone as of the burned lime, but will also be to the addi- 
tional expense of hauling and spreading 2 tons of the former to 1 of 
the latter in order to obtain the same results. 

FERTILIZING. 

Well-rotted barnyard manure which is comparatively free from 
weeds is the most satisfactory fertilizer. It should be spread on the 
land before plowing, in order that it may become thoroughly incor- 
porated with the soil. Good results also follow from heavy applica- 
tions to the preceding crop. If the manure is not available, a liberal 
application of commercial fertilizers, rich in phosphoric acid, should 
be made. The percentage of nitrogen may be low, but some nitrogen 
should be supplied for the young plants before they become inocu- 
lated and are able to secure their supply from the air. On most clay 
soils heavy applications of potash have not been profitable. A com- 
bination which has been commonly recommended is muriate of pot- 
ash, 75 to 100 pounds ; acid phosphate, 350 to 500 pounds ; and nitrate 
of soda, 50 to 75 pounds. The cheapest and most satisfactory 
method by which the consumer may obtain such a combination is to 
purchase the desired ingredients and mix them in their proper pro- 
portions. 

INOCULATION. 

Nitrogen-fixing bacteria should be provided unless the soil is known 
to be naturally supplied with these germs. This may be best accom- 
plished by scattering over the area to be seeded soil from a field upon 
which the crop has previously been successfully grown. The soil 
should be broadcasted at the rate of 250 to 500 pounds per acre and 
harrowed in immediately. The spreading should take place on a 
cloudy day or in the evening, as the sun's rays are destructive to the 
germs. Care should be taken to avoid introducing noxious weeds and 
fungous diseases. Soil from the roots of sweet-clover plants also will 
inoculate alfalfa. Another method which may be used is that of 
inoculating the seed with an artificial culture, a limited quantity of 
which can be procured from the United States Department of Agri- 
culture free of charge. Full instructions for use accompany each 
bottle of culture. The combined use of soil and artificial culture is 
recommended where both can be readily obtained. 

SEEDING. 

The seed should be sown without a nurse crop at the rate of 25 to 30 
pounds per acre. In the Piedmont section good stands are secured 



Alfalfa. 5 

-with a lighter seeding, but the heavier seedings have given the best 
results. In the coastal plain, where the soils are sandy and badly- 
infested with crab-grass, less than 25 to 30 pounds of seed per acre is 
not advisable. The seed may be drilled or else broadcasted by hand 
or with a wheelbarrow seeder and covered lightly with a smoothing 
harrow or weeder. Drilling gives a higher percentage of germina- 
tion, and as a result the rate of seeding under this practice may safely 
be somewhat less than when the seed is broadcasted. A much more 
uniform stand is secured by dividing the seed and sowing one-half 
each way of the field. The seeding may take place in the late summer 
or early fall or in the early spring. It is usually a simpler matter to 
get the ground in shape for spring seedings, and the moisture condi- 
tions are more favorable, but the weeds are apt to overwhelm the 
alfalfa before it gets a foothold, and for this reason spring seeding is 
seldom recommended. In the northern part of the region under con- 
sideration the middle of August has, on the average, given the best 
results. In the South Atlantic and Gulf States the date of seeding 
may with safety be dela} r ed as late as the 15th of October. In these 
Southern States when weather conditions are especially favorable 
successful stands are sometimes secured when the seed is sown as late 
as the first of November, but as such late seedings are much more 
subject to winterkilling and produce lighter yields the first season, 
they are not recommended. 

TREATMENT OF THE STAND. 

The alfalfa should be cut when it is just coming into blossom, or, 
Letter, when the basal shoots appear, unless the weeds threaten to 
choke out the plants before this stage is reached, in which case 
earlier cutting is recommended. The early cuttings should not be 
mowed low, as the alfalfa plants will not start so quickly and are 
more likely to be crowded out by weeds. If the first cutting should 
be light, as is usually the case if the seed is sown in the spring, it 
may be left on the land as a mulch. If it is heavy enough to smother 
the alfalfa plants it should be removed. Whenever the plants turn 
yellow the crop should be cut and removed from the field, no matter 
what the stage of development. If the stand becomes thin or patchy, 
the field should be plowed and reseeded. Attempts at patching up 
poor stands have generally proved futile. In cases where the soil has 
become so compact from pasturing or where weeds are so numerous 
as to threaten considerable injury to the crop, cultivation in the 
spring or immediately after cutting, with a weeder in the sandy soils 
or with a spike-tooth harrow 7 in the heavier soils, may be advisable. 
The alfalfa harrow, which is similar to the ordinary spring-tooth 
harrow w T ith the ends of the teeth narrow and pointed, has generally 



6 Department Circular 115, U. S. Dept. of Agriculture. 

proved very satisfactory for the purpose. No implement which wiU 
mutilate the crowns and give an opportunity for the entrance of 
diseases should be used. A top-dressing of well-rotted, weed-free 
stable manure will benefit the crop. This should be applied in the 
fall or winter and should be evenly distributed, to avoid smothering 
the plants. If the stable manure is not available, a top-dressing of 
from 300 to 500 pounds of acid phosphate per acre, with a small 
amount of potash, may prove beneficial. Alfalfa makes good pasture 
for nearly all kinds of farm animals, but under no circumstances 
should it be pastured until it has become thoroughly established or 
when the ground is wet or frozen. It should not be pastured closely 
at any time, for the grazing down of the crowns will often result in 
destruction. Owing to the difficulty of procuring a good stand in 
the East, it is very doubtful whether a farmer should take the chance 
of injuring a well-established stand by pasturing it at all. Profitable 
results have been obtained, however, by removing the first two crops 
for hay and then pasturing with hogs for the remainder of the season. 
In the fall the hogs should be removed in time to allow a 6-inch to 
8-inch growth for the protection of the plants during the winter 
months. 

For more complete information, see Farmers' Bulletin 339, en- 
titled "Alfalfa." 

June 8, 1920. 



WASHINGTON : GOVERNMENT TRINTING OFFICE : 1920 



LIBRARY OF CONGRESS 



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